Dressing apparatus for grinding wheels



Oct. 29, 1968 s. w. HOARE DRESSING APPARATUS FOR GRINDING WHEELS FiledNdv. 18, 1964 VII/1 United States Patent 3,407,800 DRESSING APPARATUSFOR GRINDINGWHEELS Stanley William Hoare, Peterborough, England,assignor to N ewall Engineering Company Limited, Peterborough, England,a British company Filed Nov. 18, 1964, Ser. No. 412,210 4 Claims. (Cl.125-11) This invention relates to apparatus for dressing grinding wheelswhich have cylindrical grinding surfaces.

According to this invention in one aspect there is provided a method ofdressing a grinding wheel employing a dressing device which has a firstdressing portion for dressing a cylindrical surface of the wheel and asecond dressing portion for dressing a surface of the wheel which facesin an axial direction or in a direction having an axial component, inwhich method the point or points of contact between the first dressingportion and the cylindrical surface of the wheel move in a directionparallel to the axis of the grinding wheel, and the second dressingportion is brought into dressing engagement with the other said surfaceof the wheel.

According to this inventionin another aspect there is provided dressingapparatus comprising a support structure, and a device for dressing agrinding wheel, which device is mounted in the support structure and hasa first dressing portion for dressing a cylindrical surface of thewheel, and a second dressing portion for dressing a surface of the wheelwhich faces in an axial direction or a direction which has an axialcomponent, the point or points of contact between the first dressingportion and the cylindrical surface of the wheel being movable laterallyfor traversing the cylindrical surface of the wheel.

The first dressing portion may comprise a single point dressing element,and in this case means is provided for moving the dressing elementlaterally for traversing the cylindrical surface of the grinding wheel.

In alternative arrangements said dressing portions are annular andcoaxial with each other, and the apparatus comprises means for rotatingthe dressing portions and means for moving at least the first dressingportion parallel to the axis of rotation of the dressing portions fortraversing the cylindrical surface of the grinding wheel. The firstdressing portion may be formed with'a series of peripheral ribs, theradially outer surfaces of which are adapted for dressing thecylindrical surface of the grinding wheel.

In other preferred arrangements the first dressing por' tion comprises amember formed with an external helical rib, the radially outer surfaceof which rib is adapted for dressing the cylindrical surface of thegrinding wheel, the second dressing portion is annular and coaxial withthe rib, and the apparatus comprises means for rotating said dressingportions about their common axis. In this construction means may beprovided for moving at least the first dressing portion parallel to saidcommon axis for traversing the cylindrical surface of the grindingwheel.

The dressing device may comprise athird dressing portion for dressing athird surface of the grinding wheel which surface faces in an axialdirection or a direction having an axial component, the second and thirdportions being disposed one on each side of the first dressing portion.

Preferably said dressing portions are all traversed together by thetraversing means.

The first dressing portion may be spaced from the second and, whereprovided, the third dressing portions by a distance piece or distancepieces, the dressing portions and distance piece or pieces beingdetachably secured together as a unit for mounting in the apparatus.

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Some embodiments of the invention will now be described by way ofexample. The description makes reference to the accompanying drawings inwhich:

FIGURE 1 shows one form of a dressing wheel accord ing to the invention,and

FIGURE 2 shows a second form of a dressing wheel according to theinvention.

For dressing the cylindrical surface 10a of a grinding wheel 10 and thetwo radiussed corner portions 10b, at the ends of the cylindricalsurface, a dressing machine or attachment 5 is provided comprising adressing wheel 6 mounted on a supporting structure 7, which is in turnmounted on compound slide structure for movement parallel to andperpendicularly to the axis of rotation of grinding wheel 10.

In the construction of dressing wheel shown in FIG- URE 1 the wheelcomprises a first annular dressing portion 11 for dressing thecylindrical surface 10a of grinding wheel 10, and second and thirdannular dressing portions 12, 13 shaped for respectively dressing thetwo corner portions 10b, 100 at opposite ends of the cylindrical surfaceof the grinding wheel 11. The dressing surfaces of dressing portions 11,12 and 13 are diamond impregnated.

The dressing portions 11, 12 and 13 are carried on a central spindle 14,which has a head 15 at one end, and are prevented from rotating relativeto the spindle by respective keys 16. Two spacing rings 17 serve tospace dressing portion 11 from portions 12 and 13 respectively. A washer18 abuts the dressing portion 13 and the assembly is secured togetherbetween the head 15 of spindle 14 and the washer 18 by a nut 19 engagedon a threaded end portion of the spindle. Head 15 is formed withradially extending recesses in which dogs 20 on a driven shaft 21engage. The spindle is journaled on centres 21a, 22 which engage incorresponding recesses in opposite ends of the spindle 14.

In use, the dressing wheel is disposed with its axis parallel to that ofthe grinding wheel. The dressing wheel is moved forward at right anglesto its axis until it is in the position shown in the drawing relative tothe grinding wheel, i.e. with one or other of the dressing portions 10b,100 in engagement with the corresponding corner portion of the grindingwheel. White the grinding wheel is rotating, the dressing wheel is thentraversed parallel to its axis of rotation so that the dressing portion11 traverses the cylindrical surface 10a of the grinding wheel. Thedressing wheel is traversed backwards and forwards with sucessive cutsand the dressing portions 12 and 13 dress the corner of the grindingwheel at the ends of the traversing movement.

The spacing rings 17 are of such a length that the dressing portion 11will traverse the full width of the cylindrical surface of the grindingwheel from the position in which the dressing wheel is shown in thedrawing before the corner portion 13 comes into contact with thecorresponding corner portion of the grinding wheel.

The traversing of the cylindrical surface of the grinding wheel by thedressing portion 11 ensures that the surface 10a of the grinding wheelis truly cylindrical and imparts to the grinding wheel the capacity toproduce a good o erall finish on the cylindrical surface to be ground.

The spacing rings 17 can be replaced by other rings having differentaxial lengths to enable grinding wheels of diiferent axial lengths to betreated.

An alternative form of dressing wheel is shown diagrammatically inFIGURE 2 and comprises two end dressing portions 24, 25 corresponding tothe portions 12 and 13 in the arrangement shown in FIGURE 1, and acentral dressing portion 26 disposed between portions 24, 25. Thecentral portion 26 has a helical rib 27 along its outer surface whichrib extends over the full length of the central portion. The dressingsurfaces of the portions 24, 25, and rib are impregnated withdiamonddust.

The central portion 26 has a greater axial length than the cylindricalsurfaces of the grinding wheel to be dressed, and the dressing wheel isused in the same apparatus and in the same way as that shown inFIGURE 1. Thus the central portion 26 engages the cylindrical surface ofthe grinding wheel while the latter is rotating about its own axis, andthe dressing wheel is rotated and moved to and fro parallel to its ownaxis to bring the two portions 24, 25 alternately into dressingengagement with the corresponding portions of the grinding wheel. Inthis arrangement however the dressing wheel 23 need be traversed only ashort distance in a direction parallel to its axis of rotation. Thisarrangement is intended for use where the arrangement shown in FIGURE 1cannot be used, for example because of possible interference with partsadjacent the grinding wheel. Alternatively, the central portion 26 mayhave the same axial length as the cylindrical surface of the grindingwheel, the dressing wheel being moved radially, without any axialcomponent, into engagement with the grinding wheel.

In another arrangement, not illustrated, the central portion 26 has aseries of spaced annular ribs and in this case the dressing wheel isrotated and traversed to and fro parallel to its own axis as in thearrangement of FIG- URE 1. v

In yet another arrangement, not illustrated, the rotary dressing portion11 in FIGURE 1 is replaced by a singlepoint diamond, and the rotarydressing portions 12 and 13 are replaced by non-rotary cutting portions.In this case the dressing device is presented to the surface of thegrinding wheel and is traversed to and fro parallel to the axis ofrotation of the grinding wheel between the positions in which the twocorner-shaping portions respectively engage the corners of the grindingwheel. As before, the distance between the corner-shaping portions isgreater than the distance between the corners of the grinding wheel to adegree such thatthe diamond can traverse the full width of theperipheral surface of the grinding wheel in the same manner as describedin relation to FIG- URE 1.

I claim:

1. A dressing apparatus for use with a grinding wheel of cylindricalform having a cylindrical curved surface, fiat end surfaces and arounded end portion between said curved surface and each of said flatend surfaces, comprising a first cylindrical dressing roller fordressing the cylindrical surface of the wheel, a second cylindricaldressing roller having a surface complementary to one of said roundedend portions of said grinding wheel, said second roller being mountedcoaxially with respect to said first roller, means for rotating saidrollers about an axis parallel to that of said grinding Wheel, means formoving said rollers in an axial direction, a sufficient distance tocause said first roller to traverse the full width of the cylindricalsurface of said grinding wheel, said first and second grinding rollersbeing spaced along said common axis such that said second grindingroller contacts the 4 rounded end portion of said grinding wheel onlyafter said first roller has reached the opposite end thereof.

2. Dressing apparatus as claimed in claim 1 further comprising a thirdcylindrical dressing roller having a surface complementary to therounded end portion of said grindingwheel opposite that contacted bysaid second dressing roller,.said third dressing roller being mountedfor rotation and axial movement on the side of said first dressingroller opposite that of said second dressing roller, said first andthird dressing rollers being spaced along said common axis such thatsaid third dressing roller contacts its respective rounded end portionof said grinding wheel, only after said first roller has reached theother end thereof.

3. A method of dressing a grinding wheel of cylindrical form having acylindrical curved surface and flat end surfaces and a rounded portionbetween said curved surface and each of said flat end surfaces,comprising the steps of bringing into engagement with said curvedsurface a first cylindrical dressing roller, the axes of said firstdressing "roller and said grinding wheel being parallel at the time ofengagement; traversing said firstcylindrical roller in a first axialdirection to dress the full width of the cylindrical surface of saidgrinding wheel; bringing into engagement, after said traversing in saidfirst axial direction, with one of said rounded portions and said fiatsurfaces of said grinding wheel, a second dressing roller, said seconddressing roller having a surface complementary to said rounded portionand said flat surface, said second roller being mounted coaxially withand spaced apart from said first roller.

4. A method as set forth in claim 3 further comprising after saidtraversing in said first axial direction, traversing said firstcylindrical roller in a second axial direction opposite to said firstaxial direction to dress the full width of the cylindrical surface ofsaid grinding wheel, and then bringing into engagement with the other ofsaid rounded portions and said fiat surfaces of said grinding wheel athird dressing roller, said third dressing roller having a surfacecomplementary to said other rounded portion and said other fiat surfaceand said third roller being mounted co-axially with and spaced apartfrom said first and second dressing rollers.

References Cited UNITED STATES PATENTS 1,867,939 7/1932 Davenport -112,648,172 8/1953 Silven 125-11 X 2,730,848 1/1956' Wallace 125-39 X2,770,925 11/1956 Wallace 125-11 X 2,777,260 1/1957 Mahlmeister 125-11 X3,017,875 1/1962 Jones 125-11 3,157,174 11/1964 Emery 125-39 X 2,975,7823/1961 Balsiger 125-11 1 FOREIGN PATENTS 594,556 11/1947 Great Britain.

HAROLD D. WHITEHEAD, Primary Examiner.

1. A DRESSING APPARATUS FOR USE WITH A GRINDING WHEEL OF CYLINDRICALFROM HAVING A CYLINDRICAL CURVED SURFACE, FLAT END SURFACES AND AROUNDED END PORTION BETWEEN SAID CURVED SURFACE AND EACH OF SAID FLATEND SURFACES, COMPRISING A FIRST CYLINDRICAL DRESSING ROLLER FORDRESSING THE CYLINDRICAL SURFACE OF THE WHEEL, A SECOND CYLINDRICALDRESSING ROLLER HAVING A SURFACE COMPLEMENTARY TO ONE OF SAID ROUNDEDEND PORTIONS OF SAID GRINDING WHEEL, SAID SECOND ROLLER BEING MOUNTEDCOAXIALLY WITH RESPECT TO SAID FIRST ROLLER, MEANS FOR ROTATING SAIDROLLERS ABOUT AN AXIS PARALLEL TO THAT OF SAID GRINDING WHEEL, MEANS FORMOVING